That listing of the old grading bands was exactly what I was looking for. It was really only to satisfy my curiosity, though, not for any desire to actually engage in discussion of the minutiae of how such systems work. You said in that earlier message: "Given you are the only person who has expressed an interest to date" - since then, a number of people seem to have taken more of an interest, so maybe there is someone among those who have replied here who could double check your thoughts? As I said in my reply to the pm you sent me, I don't have any great knowledge of statistics.